1. Field of the Invention
The present invention provides a projecting apparatus, and more particularly, to a projecting apparatus with a reflective light valve.
2. Descriptions of the Related Art
FIG. 1 illustrates a schematic view of a conventional projecting apparatus. The projecting apparatus may comprise a light source 11, a reflecting mirror 12 and a reflective light valve 13. The light source 11 can emit a light beam 111 to the reflecting mirror 12, while the reflecting mirror 12 can reflect the light beam 111 to the reflective light valve 13. The reflective light valve 13 can also reflect the light beam 111, and control the reflection angle of the light beam 111 so that a portion of the light beam 111 is projected outside the projecting apparatus while the remaining portion of the light beam 111 stays inside the projecting apparatus. The projecting apparatus may further comprise a housing 14 for accommodating the light source 11, the reflecting mirror 12 and the reflective light valve 13 therein.
In conventional projecting apparatuses, the light source 11 must be arranged obliquely with respect to the reflective light valve 13 to project the light beam 111 to the reflecting mirror 12 at a specific angle. Only in this way can the light beam 111 reflected by the reflecting mirror 12 be projected to the reflective light valve 13 at another specific angle, so that the reflective light valve 13 can reflect a portion of the light beam 111 to the outside of the projecting apparatus.
However, arranging the light source 11 obliquely leads to some drawbacks of the projecting apparatus as listed below for example:                1. The light source 11 occupies a large space when being arrange obliquely. Furthermore, in other optical components, such as light uniformizing components, the relay lens that are optically coupled with the light source 11 must also be arranged obliquely, thereby, occupying a large space. Thus, the housing 14 must be made to have a large thickness to provide a sufficient space for accommodating the light source 11 and these optical components. In other words, the oblique arrangement of the light source 11 has impeded the tendency of making the housing 14 thinner.        2. When the light source 11 is arranged obliquely, a side of the light source 11 is disposed very close to the housing 14 to make the space between this side of the light source 11 and the housing 14 insufficient. Consequently, the air flow through this side of the light source 11 will be very limited, which makes it difficult to dissipate heat from this side through air convection.        
Accordingly, an urgent need exists in the art to provide a projecting apparatus capable of overcoming at least one of the above drawbacks.